The present invention relates to an optical technique for providing a forgery preventing effect, decorative effect, and/or aesthetic effect.
Articles such as securities, certificates, brand items, electronic apparatuses, and personal authentication media are desirably difficult to forge. Therefore, articles like these are sometimes made to support display members having a high forgery preventing effect.
Many such display members include microstructures such as diffraction gratings, holograms, and lens arrays. These microstructures change colors in accordance with, e.g., changes in observation angle. Also, these microstructures are difficult to analyze and forge. Accordingly, display members like these can achieve a relatively high forgery preventing effect.
Note that as a technique pertaining to a display member as described above, there is a technique by which a pixel is divided into three portions as RGB channels, and a photograph-quality color image is expressed by a diffraction structure by area coverage modulation in these channels.